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A Dynamic Wall Model Constrained by RANS Reynolds Stress

APS Meeting Abstracts, 2009
We discuss a dynamic wall model obtained by incorporating RANS constraints into a dynamic SGS model. Unlike conventional approaches, Reynolds stresses are used as constraints on the mean SGS stress so that the constraining Reynolds stress closely matches the ......Read more
Abstract Submitted for the DFD09 Meeting of The American Physical Society A dynamic wall model constrained by RANS Reynolds stress 1 AMAN VERMA, NOMA PARK, KRISHNAN MAHESH — We discuss a dynamic wall model obtained by incorporating RANS constraints into a dynamic SGS model. Unlike conventional approaches, Reynolds stresses are used as constraints on the mean SGS stress so that the constraining Reynolds stress closely matches the com- puted stress only in the mean sense. We use the Germano-identity error as an indicator of LES quality so that the RANS constraints are activated only where the Germano-identity error exceeds a certain threshold. The proposed model is applied to LES of turbulent channel flow at various Reynolds numbers and grid resolutions to obtain significant improvement over the dynamic Smagorinsky model, especially at coarse resolutions. The model has been implemented in spectral and structured finite volume solvers and is being extended to an unstructured solver. These devel- opments will be discussed. 1 This work was supported by the United States Office of Naval Research under ONR Grant N00014-05-1-0003. Aman Verma University of Minnesota Date submitted: 06 Aug 2009 Electronic form version 1.4
Abstract Submitted for the DFD09 Meeting of The American Physical Society A dynamic wall model constrained by RANS Reynolds stress1 AMAN VERMA, NOMA PARK, KRISHNAN MAHESH — We discuss a dynamic wall model obtained by incorporating RANS constraints into a dynamic SGS model. Unlike conventional approaches, Reynolds stresses are used as constraints on the mean SGS stress so that the constraining Reynolds stress closely matches the computed stress only in the mean sense. We use the Germano-identity error as an indicator of LES quality so that the RANS constraints are activated only where the Germano-identity error exceeds a certain threshold. The proposed model is applied to LES of turbulent channel flow at various Reynolds numbers and grid resolutions to obtain significant improvement over the dynamic Smagorinsky model, especially at coarse resolutions. The model has been implemented in spectral and structured finite volume solvers and is being extended to an unstructured solver. These developments will be discussed. 1 This work was supported by the United States Office of Naval Research under ONR Grant N00014-05-1-0003. Aman Verma University of Minnesota Date submitted: 06 Aug 2009 Electronic form version 1.4